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Fixed #5022 (Improve check: Division by zero or useless condition, function call)

This commit is contained in:
Daniel Marjamki 2013-09-15 17:46:52 +02:00
parent 19745bbb7d
commit 3de9431507
2 changed files with 66 additions and 5 deletions
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63
lib/checkother.cpp
View File

@ -2165,7 +2165,7 @@ void CheckOther::checkZeroDivisionOrUselessCondition()
for (std::size_t functionIndex = 0; functionIndex < numberOfFunctions; ++functionIndex) {
const Scope * scope = symbolDatabase->functionScopes[functionIndex];
for (const Token* tok = scope->classStart->next(); tok != scope->classEnd; tok = tok->next()) {
if (Token::Match(tok, "[/%] %var% !!.")) {
if (Token::Match(tok, "[/%] %var% !!.") || Token::Match(tok, "[(,] %var% [,)]")) {
const unsigned int varid = tok->next()->varId();
const Variable *var = tok->next()->variable();
if (!var)
@ -2177,8 +2177,61 @@ void CheckOther::checkZeroDivisionOrUselessCondition()
break;
}
}
const Token *tok2;
const Token *divtok = tok;
// Check if variable is divided by function..
if (Token::Match(tok, "[(,]")) {
const Token *ftok = tok;
unsigned int parnum = 0U;
while (ftok && ftok->str() != "(") {
if (ftok->str() == ")")
ftok = ftok->link();
else if (ftok->str() == ",")
parnum++;
ftok = ftok ? ftok->previous() : NULL;
}
ftok = ftok ? ftok->previous() : NULL;
if (!Token::Match(ftok, "%var% (") && ftok->function())
continue;
const Function * const function = ftok->function();
const Variable * const arg = function ? function->getArgumentVar(parnum) : NULL;
const Token *argtok = arg ? arg->typeStartToken() : NULL;
if (!argtok)
continue;
if (argtok->str() == "const")
argtok = argtok->next();
if (!Token::Match(argtok,"%type% %var% ,|)"))
continue;
const Scope * const functionScope = function ? function->functionScope : NULL;
if (!functionScope)
continue;
const unsigned int varid2 = argtok->next()->varId();
divtok = NULL;
bool use = false;
for (const Token *tok2 = functionScope->classStart->next(); tok2 != functionScope->classEnd; tok2 = tok2->next()) {
if (Token::Match(tok2, "[%/] %varid%", varid2)) {
divtok = tok2;
tok2 = tok2->next();
} else if (tok2->str() != "&" && Token::Match(tok2, "%cop% %varid%",varid2)) {
tok2 = tok2->next();
} else if (tok2->varId() == varid2 || tok2->str() == "{") {
use = true;
break;
}
}
if (!divtok || use)
continue;
}
// Look for if condition
const Token *tok2;
for (tok2 = tok->tokAt(2); tok2; tok2 = tok2->next()) {
if (tok2->varId() == varid)
break;
@ -2193,11 +2246,11 @@ void CheckOther::checkZeroDivisionOrUselessCondition()
if (tok2->str() == "{")
break;
if (isVarUnsigned && Token::Match(tok2, "(|%oror%|&& 0 < %varid% &&|%oror%|)", varid))
zerodivcondError(tok2,tok);
zerodivcondError(tok2,divtok);
else if (isVarUnsigned && Token::Match(tok2, "(|%oror%|&& 1 <= %varid% &&|%oror%|)", varid))
zerodivcondError(tok2,tok);
zerodivcondError(tok2,divtok);
else if (Token::Match(tok2, "(|%oror%|&& !| %varid% &&|%oror%|)", varid))
zerodivcondError(tok2,tok);
zerodivcondError(tok2,divtok);
}
}
}

8
test/testother.cpp
View File

@ -456,6 +456,14 @@ private:
"}");
ASSERT_EQUALS("[test.cpp:3] -> [test.cpp:2]: (warning) Either the condition 'x!=0' is useless or there is division by zero at line 2.\n", errout.str());
// function call
check("void f1(int x, int y) { c=x/y; }\n"
"void f2(unsigned int y) {\n"
" f1(123,y);\n"
" if (y>0){}\n"
"}");
ASSERT_EQUALS("[test.cpp:4] -> [test.cpp:1]: (warning) Either the condition 'y>0' is useless or there is division by zero at line 1.\n", errout.str());
// avoid false positives when variable is changed after division
check("void f() {\n"
" unsigned int x = do_something();\n"